[PATCHv2,0/3] uprobe: uretprobe speed up

Message

Jiri Olsa April 2, 2024, 9:32 a.m. UTC

hi,
as part of the effort on speeding up the uprobes [0] coming with
return uprobe optimization by using syscall instead of the trap
on the uretprobe trampoline.

The speed up depends on instruction type that uprobe is installed
and depends on specific HW type, please check patch 1 for details.

I added extra selftests to check on registers values before and
after uretprobe to make sure the syscall saves all the needed regs
and that uprobe consumer can still change registers.

Patch 1 is based on:
  https://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace.git
  probes/for-next

and patches 2,3 are based on bpf-next/master and can be taken
separately through bpf-next tree without patch 1.

v2 changes:
  - reposted to proper tracing mailing list [Masami]
  - renamed selftest trigger functions [Andrii]
  - kept bpf_testmod register call pattern [Andrii]
  - added acks [Andrii/Oleg]

thanks,
jirka


[0] https://lore.kernel.org/bpf/ZeCXHKJ--iYYbmLj@krava/
---
Jiri Olsa (3):
      uprobe: Add uretprobe syscall to speed up return probe
      selftests/bpf: Add uretprobe syscall test for regs integrity
      selftests/bpf: Add uretprobe syscall test for regs changes

 arch/x86/entry/syscalls/syscall_64.tbl                  |   1 +
 arch/x86/kernel/uprobes.c                               |  83 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/syscalls.h                                |   2 ++
 include/linux/uprobes.h                                 |   2 ++
 include/uapi/asm-generic/unistd.h                       |   5 +++-
 kernel/events/uprobes.c                                 |  18 +++++++++---
 kernel/sys_ni.c                                         |   2 ++
 tools/include/linux/compiler.h                          |   4 +++
 tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c   | 122 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c | 230 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 tools/testing/selftests/bpf/progs/uprobe_syscall.c      |  15 ++++++++++
 11 files changed, 478 insertions(+), 6 deletions(-)
 create mode 100644 tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c
 create mode 100644 tools/testing/selftests/bpf/progs/uprobe_syscall.c